* Cells (1 × 106 cells in 0.1 ml PBS) were subcutaneously injected into the posterior flank of a female athymic nude mouse (3 mice per group). The mice were monitored daily for tumor growth at the site of inoculation. Animals in which tumor did not form were observed for additional 1 week. The latency was determined as the period of time required by tumors to reach a diameter of 0.5 cm. Results were from one of two experiments with similar outcomes.